Despite being a high tier character in Super Smash Bros. 4 (ranked 15th out of 55 characters), Pikachu has been noticeably buffed during the transition to Ultimate. Its overall speed has been increased and most of its moves have much less ending and landing lag, increasing Pikachu's combo potency. Its most significant buff is its altered neutral air and down air, the former now acting like Mewtwo's neutral air and having combo potential, and the latter obtaining the ability to meteor smash which gives it two different attacks that have better hitboxes and better kill power which were some of its biggest weaknesses in Smash 4. Back air auto-canceling in a short hop and sending in a consistent direction make it possible to combo the attack into itself at low percents and send people off stage in one interaction, which can immediately cause a KO against characters with bad recoveries. Its kill power was also improved due to many moves dealing more knockback, like dash attack, forward air, up air, down smash and Thunder. Pikachu also greatly benefits from Ultimate's mechanics as it makes its already incredible and oppressive edgeguarding even more terrifying as it is no longer possible to airdodge through Thunder.

However, Pikachu is not without its nerfs, the most significant being the increased startup and ending lag on its grabs and the altered knockback of up throw, which worsens its combo potential with Thunder. The removal of Quick Attack cancelling also reduces its mobility.
Pikachu also still suffers from its weaknesses: lack of range, no setups for its KO moves, bad general endurance due to being one of the 10 lightest characters and having above average gravity and falling speed and inconsistent KO ability due to possessing sourspots on its smash attacks or attacks with below average power. It also is hindered by the buffs to swordfighters and the additional fighters with disjointed range, giving it new tough matchups.
Despite that, Pikachu's buffs have made it even more of a potent fighter than in Smash 4, which has led to many professionals such as Samsora and ESAM putting it as a top tier character. In fact, Mew2King and ZeRo went as far as to put Pikachu as the single best character in the game. However, it's debatable if it deserves the top tier status.

Like all veterans returning from Smash 4, Pikachu has a more subdued color scheme, more closely resembling its appearance in recent mainline Pokémon games.

Pikachu is more expressive. It now appears angry during many attacks. It also has a new angry expression.

Pikachu now faces the foreground at an angle, instead of facing directly forward. In addition, it always faces the screen regardless of which direction it turns, causing all of its animations to be mirrored.

It deals less knockback (10/9/8 base/45 scaling → 12/18 base/20/30 scaling). Combined with the increased traction across the cast, this allows Pikachu to connect more hits against opponents before they are pushed out of range.

It has gained a shieldstun multiplier of 1.8×. Combined with its reduced ending lag and the increased shieldstun for ground attacks, this makes it much safer on shield, with the clean hit being only barely punishable by a shield grab.

The early hit has a shorter duration, which causes the clean and late hits to be active earlier, and the late hit has a longer duration (frames 15-17 (early)/18-20 (clean)/21-22 (late) → 15-16/17-19/20-29).

Forward smash has more ending lag (FAF 49 → 54).

The clean hit and the late hit during its latest active frames have a smaller hitbox (4.1u → 3.6u (clean), 5.2u → 4u (late)).

The clean hit has less base knockback during its first frame (60 → 50), making its KO ability less consistent.

The first three hits use the autolink angle (367°). This allows Pikachu to drag opponents down with the move and combo into many of its ground attacks, which is further complemented by its lower landing lag.

The last hit launches at a more vertical angle (361° → 60°). Combined with its multi-hit nature, this improves its combo potential.

Down aerial has gained a clean hit during its first two active frames, which deals more damage (12% → 13%) and meteor smashes opponents (361° → 270°), with knockback not fully compensated (20 base/84 scaling → 16/86). This allows it to start combos onstage and improves Pikachu's edgeguarding ability.

Back throw releases the opponent faster (frame 31 → 26), with its total duration unchanged. This increases its ending lag and shortens the distance Pikachu moves back before throwing, making it less effective for setting up edgeguards, while still giving the opponent enough time to DI.

Down throw inflicts 9 frames of hitlag on the opponent upon release. While making it easier to react to, this noticeably improves its combo potential.

The first hit is coded to disappear on the same frame it comes out. As a result, the throw deals less damage (8% → 5%) and no longer hits bystanders, but oddly enough, Pikachu and the thrown opponent still experience hitlag from the first hit.

Volt Tackle involves Pikachu dashing forward quickly while surrounded by a ball of electricity. If this initial attack connects, Pikachu traps the opponent in place and speeds around the stage at different angles, racking up damage before launching opponents with an electric blast at the end of the move.

Volt Tackle is easier to control, requiring only a single button press rather than having to control Pikachu's slippery movement.

Pikachu can no longer chase down opponents if the initial attack misses, and may self-destruct if initiated too close to the edge.

Even though Pikachu is widely considered a top tier, it has been further buffed by game updates. However, these buffs are very minor, only increasing its grab range slightly and speeding up its pummel.

An electrified double kick performed from the baby freeze, a variation of the freeze breakdancing move. It deals more damage when angled upward, and the lower angles semi-spike. Deals moderate knockback; the unangled version KOs Mario around 155% at the edge of Final Destination.

An overhead tail swipe, starting from behind Pikachu. An excellent combo starter, comboing into itself at low percents and into Pikachu's aerials at low to mid percents. A powerful juggling tool. Has moderate startup lag, however, as it does not hit opponents in front of Pikachu until frames 9-10, depending on their size.

A battering ram. The early hitbox deals solid damage and good knockback, allowing it to KO middleweights around 135% on Final Destination. It also has fairly low startup lag (frame 6), and the early hitbox lasts deceptively long. However, the late hitbox has no KO potential at any reasonable percent, and the high ending lag prevents either hit from comboing.

Rears its head back before leaning forward and releasing a large orb of electricity in front of it, leaving a trail of electricity. The early hit comes out on frame 15, the clean hit on frame 17 and the late hit on frame 20. The center of the ball deals the most damage and knockback, having high horizontal KO potential. The trail deals the second most damage and the least knockback, and the tip deals the least damage and second most knockback. Has good range, with a hitbox the close to the size of Pikachu. The uncharged sweetspot KOs Mario around 80% at the edge of Final Destination, although the early hit doesn't KO until 105% and the late hit until 100%, giving the attack several sourspots and making it very inconsistent. Also has a long duration and noticeable ending lag, making it punishable if shielded or dodged.

An overhead tail swipe. Unlike Pikachu's up tilt, it starts in front of it and has good vertical KO potential. The early hit comes out somewhat quickly (frame 10) and lasts until Pikachu's tail goes above it, after which the clean hit lasts until the tail goes behind it. The early hit's sweetspot is located on Pikachu's body, and is very difficult to land outside a shield break punish. The early sweetspot KOs middleweights around 115% on Final Destination, while the early sourspot KOs around 125%. The late hit, however, deals minimal damage and knockback.

Charges its tail with electricity before spinning it around, shocking opponents. Has the least damage potential out of all its smash attacks, dealing only 13%. It KOs middleweights around 95% at the edge of Final Destination and deals good horizontal knockback. Also has the least start-up out of all its smash attacks, coming out on frame 8, but its 42 frames of ending lag makes it very punishable if used poorly.

Poses while charging itself with electricity, shocking nearby opponents. Hits 4 times. One of Pikachu's most versatile tools; it is useful for breaking out of combos due to its very fast startup (frame 3), can combo into itself offstage at very low percent, can be used to drag down opponents for edgeguarding offstage, or for comboing into jab, up tilt, forward tilt, down tilt, grab, or even up smash. Autocancels in a short hop.

Spins its forward with an electrically charged head, shocking opponents. Moderate startup lag at frame 11 and hits 6 times. Has low landing lag, making it an effective spacing option, but has very small looping hitboxes and does not use the autolink angle. The multiple hits and long duration make it an effective aerial for SHFFing.

Spins around horizontally, hitting multiple times, with a pose at the end to launch foes. Very fast, coming out on frame 4, but it's below average knockback doesn't make it reliable for KOing until very high percents and has terrible range, only covering Pikachu's limbs. At such it's more useful for combos. Can drag down opponents, and has a landing hitbox. It has 18 frames of landing lag, however.

Points down and spins its head downwards, launching opponents. The clean hit is a powerful meteor smash, while the late hit has good horizontal knockback. Has a landing hitbox. However it has 22 frames of landing lag.

Rolls backwards before launching the opponent. Very good for setting up edgeguards, as it has high base knockback and the animation means opponents near the center will end up being launched near the edge, but it is unimpressive as a KOing option as it only starts KOing middleweights around 165% at the edge of Final Destination.

Shoots a ball of electricity. A very useful projectile, as it deals good damage, moves quickly, and can be used repeatedly. When it goes over the edge, it sticks to the platform it's on, looping around until its lifespan is over or it hits the bottom of a soft platform. This property allows it to be used to annoy opponents trying to recover by using it near the edge and hitting them when they attempt to grab it.

Charges up before launching forward at a high velocity. Can be charged to increased damage, knockback, and distance. Useful for horizontal recovery, as it has a hitbox protecting it, high horizontal distance, and can sweetspot the ledge. Can also be used to punish shield breaks due to its high knockback when charged; however, it has high ending lag. If inputted like a smash attack, it immediately starts with some charge.

Zips upward at high speeds, dealing damage to opponents on contact. Can be angled; if angled in a different direction after the first time it is used, Pikachu will use it again. It covers great distance and can be unpredictable if used well, but it leaves Pikachu helpless. It's also an approach option, however in this case it can be predictable and it is unsafe on shield. Pikachu also cannot use the Quick Attack canceling tecnique anymore.

Calls down a bolt of lightning from the sky. If the bolt strikes Pikachu, it will create an electric explosion around itself, dealing massive knockback and granting Pikachu intangibility for 10 frames. If an opponent is struck near the top of the bolt, they're launched down into Pikachu; otherwise, they're launched upwards. Has high endlag if the bolt doesn't strike Pikachu.

Any number following the Smasher name indicates placement on the Spring 2019 PGRU, which recognizes the official top 50 players in the world in Super Smash Bros. Ultimate from February 1st, 2019 to July 7th, 2019.

Each character can be unlocked by clearing Pikachu's Classic Mode, or the Classic Mode of any preceding character, if all preceding characters have been unlocked. Once all the above characters are unlocked, clearing Classic Mode with any of them will default to Mario's character unlock tree, starting with Sonic.

Pikachu was among the fighters summoned to the cliffside to fight an army of Master Hands.

During the opening cutscene, Pikachu was present when Galeem unleashed his beams of light. While attempting to run away, Pikachu was noticed by Sonic, who slowed down for Pikachu in an attempt to save it. However, both of them were vaporized and placed under Galeem's imprisonment along with the rest of the fighters, except for Kirby.

Pikachu can later be found stuck on an island that can only be accessed by falling into the current of a waterfall, then the player must confront the spirit of Esna before they can battle to awake it.

Pikachu's Fighter Spirits can be obtained by completing Classic Mode. They are also available periodically for purchase in the shop for 500 coins. Unlocking Pikachu in World of Light allows the player to preview the first spirit below in the Spirit List under the name "???". As Fighter Spirits, they cannot be used in Spirit Battles and are purely aesthetic. Each Fighter Spirit has an alternate version that replaces them with their artwork in Ultimate.

Due to its new Pikachu Libre skin, Pikachu is now the only member of the Original 12 to change sex between costumes, as well as the first of the Original 12 to technically be a different character in one of its costumes (while characters like Link and Captain Falcon have costumes resembling distinct characters before like Fierce Deity Link or Blood Falcon, clear differences show them to not be the real thing, such as maintaining the same body underneath their clothes or a difference in shoes).